Pittsburgh & San Francisco: Sister Measles Cities

Not to be outdone by San Francisco, Pittsburgh joined the 2014 measles club after atleast 1 case was diagnosed here.

The facts surrounding the case in Pittsburgh serves to reinforce some important points about measles:

1. Measles is extremely contagious: the case patient in Pittsburgh traveled on public buses. As measles can infect 90% of those exposed that are susceptible to infection, secondary cases are to be expected.

2. Measles is a world traveler the couldn't resist one of the nation's most livable city: the case patient traveled to New York and was exposed to someone who contracted the disease overseas.

3. High vaccination rates are needed for herd immunity: because of its marked contagiousness, communities need to have vaccination rates above 90% to halt transmission.  Children under 1 year of age are a group too young to be vaccinated and are reliant upon herd immunity for protection, as are those whose vaccine failed to provide full immunity.

Hopefully this case will prompt those who have deferred or declined vaccination to seal some holes in the Pittsburgh herd's immunity. Next up should be our potholes. 

Calling UTIs Mundane: A Privilege to Be Earned

Today I was the instructor/facilitator for a problem-based learning (PBL) session for 1st year medical students in their microbiology course. 

The "problem" we worked through was a urinary tract infection (UTI). As an infectious disease physician, I often find myself scorning at consultation requests for UTIs. UTIs are usually  e mundane and lack the excitement or intellectual change of, for example, a fever in a returned traveler.

By working through the case with the med students, however, I realized mundaneness  depends upon one's context of knowledge. That UTIs have become mundane is testament to the fact that I have internalized the principles of infectious disease management and UTIs, with minimal cryptic elements, allow all these principles to be apparent in a very concrete manner. Such principles that readily available include: host defense mechanisms, bacterial virulence, risks for resistance, alterations in host immunity, and iatrogenic risk factors. 

It was extremely fun to try and bring these principles alive in the mind of the students allowing them to internalize the principles. 

It is a privilege to be able to think of a UTI as mundane. 

Smallpox and Stage Fright

I'm currently listening to the audio versions of the multi-part Lyndon Johnson biography by Robert Caro and, especially for those who like the Netflix series House of Cards, it is a must read as it portrays naked power-lust and secondhandedness on a grand scale. 

One infectious disease tidbit that I found in the books is interesting. Describing Lady Bird Johnson, the books relate that as a child she was so afraid of public speaking that she hoped that if she ended up salutatorian or valedictorian of her high school and was required to give a speech at graduation, she would contract smallpox and be excused. She ended up 3rd in her class. 

That's a bad case of stage fright for a future First Lady. 

With a mortality rate that could reach 30%, wishing for chickenpox or influenza would be much more advisable than hoping for smallpox.

Today, modern stage fright sufferers don't have the "luxury" of wishing smallpox on themselves as DA Henderson has removed that option.

Stealthy Pathogens & Blind Alleys

An interesting paper highlighting the ability of the relatively rare pathogens called Microsporida to exploit organ transplantation and the consequent immunosuppression was published in Annals of Internal Medicine. 

The case centers on a donor, originally from Mexico who asymptomatically harbored the Microsporida, died, and had her kidneys and lungs harvested and transplanted into 3 individuals. These individuals all developed symptoms consistent with infection and had extensive evaluations. Because the donor was suspected to have eaten unpasteurized cheese, another rare pathogen--Brucella--was considered and tests were positive in the recipients. However, treatment for Brucella did not improve the patients' conditions. Eventually, the correct diagnosis was arrived at and treated.

This case illustrates something awesome about infectious diseases--all the detective work, blind alleys, and false leads involved in making the correct diagnosis. 

In this case you have 3 organ transplant patients sick with something possibly donor derived. The donor is from Mexico and may have eaten unpasteurized cheese, a known risk factor for brucellosis. But, she turned out to have acquired Microsporidia which she likely acquired from exposure to animal excretions. 

The editorial that accompanies the paper talks of stealthy and unexpected pathogens that accompany transplanted organs. Wouldn't it be cool to have special eyes to see these things, sort of how antibodies are likened to soldiers with special vision in my favorite children's book. 

Blending Stool into Chocolate Milk

Clostridium difficile has become a scourge in hospitals and is beginning to be viewed as a Medicare "no pay" condition. This infection is fundamentally the result of a disruption of the microbiome making the human colon hospitable to C.diff. When antibiotic treatment, which further disrupts the microbiome, is insufficient, few options exist.

The option with the most promise--which is almost per se unpalatable--is a fecal transplant. This involves reconstituting the microbiome of the patient and crowding out C.diff. When used, often as a last resort, it works. The stool can be administered via a nasal feeding tube or via colonoscopy.

A story in The New York Times is focused on a stool bank (Openbiome) that offers donor stool for use in these infections. The advantage of a stool bank is that it provides a source of donor stool that has been screened for the presence of pathogens and is safe to instill. This innovative thinking by Openbiome is admirable.

My favorite quote from the article: "a technician blended the donor’s stool into preparations that looked like chocolate milk."